The Orenda Startup™ is about the LSI, Not Just Calcium

Many people think the Orenda Startup™ is basically a "Calcium Startup". But that's incorrect, and we want to set the record straight. The Orenda Startup™ is an LSI startup. ₁₀₄




We embrace calcium hardness and are not ashamed of it. Calcium is the most misunderstood chemistry in the pool business, in our opinion, and it gets a bad rap. Water chemistry becomes much more simple and more predictable with good calcium hardness levels. LSI Balance and Calcium Management is the first of our Four Pillars of Proactive Pool Care. Suffice it to say, much of the Orenda philosophy is about balancing pool chemistry–like the LSI–and calcium is a reliable way to do it. And balanced water is critical to pool plaster...(and for that matter, painted pools, vinyl liner, and fiberglass too).

Calcium is just a means to a desired LSI. And it's not the only one

Given that the LSI is an index to measure the saturation of calcium carbonate, you might think it's all about calcium...but there are 5 other factors that impact the LSI. You can have balanced LSI water with 100 ppm calcium just like you can have it balanced at 1000 ppm calcium. That said, both are difficult to manage, and especially on a pool startup, we want an LSI that is just slightly positive, on purpose.

The idea of filling a pool with slightly positive-LSI water (+0.20 and above) was not an Orenda idea. We assume many builders and pool service technicians have tried treating water as it is filling up; and have probably been trying for decades or more. But yet, it never went mainstream, probably because of the difficulty of pulling it off without issues. Now our startup has become mainstream, with countless pools as testimony to its effectiveness.

The earliest method for pre-treating water on startups [that we know of] was "The Bicarb Startup." Like ours, the Bicarb Startup method was forged out of necessity, it consistently works, and it's affordable...but it takes extra time and effort up front. Both methods share the same goal: feed the water the LSI balance it craves so the plaster can cure in peace, without water stealing calcium from it. It's a simple objective with more than one way to do it.

The first company that introduced Orenda to the notion of adding calcium during the startup was Blue Moon Pools, a pool renovation company in San Diego. They discovered that adding even small amounts of calcium early on made a big difference. Here's their video showing the difference between the spa (which just filled with water) and the pool (in which they added SC-1000 and calcium early on).


We prefer calcium first and bicarb second, mainly because calcium stays consistent. It pretty much stays where you leave it, which gives us a foundation to build LSI balance upon. Bicarb can do so too, but acid can reduce alkalinity, so it's less consistent than calcium.

That being saidif your source water already has our desired 300 ppm of calcium hardness, you do not need to add any more calcium. If you have 300+ calcium out of the tap, you should instead adjust alkalinity and/or pH until you reach the desired LSI. The goal is to have a combined 400 and 500 ppm of alkalinity and calcium (together). As long as you have these three targets met, you should be fine:

  1. Minimum 300 ppm calcium hardness
  2. Minimum 100 ppm total alkalinity
  3. LSI between +0.20 and +0.50

Orenda does not require–nor encourage–people to always add calcium on a startup. Tap water chemistry dictates everything. This is why it's so important to test the tap water. You need to know what is filling the pool.

Example: The source water for a new 20,000 gallon pool has 310 ppm calcium, 60 ppm alkalinity and a 7.6 pH. The LSI of the source water @ 65ºF is -0.17. The desired range of LSI is +0.20 - +0.50, which is slightly elevated, on purpose.

One way to start this pool up is to raise the alkalinity to 150 ppm, which brings our LSI into the desired range, at +0.23. For this 20,000 gallon pool, that takes 26.44 pounds of sodium bicarbonate. See the screenshot.

orenda app, orenda startup, add alkalinity, add sodium bicarbonate

Why even bother with an LSI startup?

You may be thinking this is a lot of extra work, and unnecessary. Well, consider this: every speck of plaster dust that comes out of the surface is carbonated calcium that should have cured within the cement. You can hide it all you want with startup products like SC-1000, or hot start to burn up the dust. But neither of those methods address the real problem. You cannot put calcium back into the surface after it has been taken.

We know from the research done by the National Plasterers Council, the American Concrete Institute and the Portland Cement Association that the curing process takes time. During the curing time, plaster is at its most vulnerable. Calcium Hydroxide (Ca(OH)2) remains soluble until it carbonates into calcium carbonate (CaCO3) to reinforce the strength of the cement...and that curing process takes months.

We also know that slightly-positive LSI removes the water's ability to leech out calcium from a new surface. Water is incapable of over-saturating itself with calcium. So...........if we prevent the water from stealing valuable calcium while the plaster is most vulnerable, that's a good thing.

But back to the question: why even bother? Pools have been started up with acid for decades. Hey, nobody is forcing you to do it our way, or even listen to us. Feel free to continue doing hot starts, or traditional startups with days and days of brushing plaster dust, adding acid, and repeating. Whatever you believe is in the homeowner's best interest.

Problems that can occur with the Orenda Startup™

Before listing the potential problems, let's be clear: if you do not follow our procedure as directed and have issues, that is not a failure of our procedure. Do not expect to do half our procedure and get 100% of the results. We have had people blast our process for not working...then we come to find out they only added SC-1000 and calcium, and ignored the rest of the procedure. Adding calcium and SC-1000 alone is not the entire process.

Here is the written 5-day startup procedure, and below is the video explaining the entire fill-up day process.


Missing the mark (low)

When you miss the target LSI on the low side (meaning not enough calcium or alkalinity, or not fast enough), the pool's water will likely have a spiked pH and some plaster dust. It's usually significantly less plaster dust than normal, because even if you miss the mark, you're still adding calcium or bicarb to get closer to the LSI than the normal tap water alone. The simplest remedy for this is what we call the switcheroo. The pool needs to be LSI balanced...but you're looking at water that already balanced itself by eating some calcium hydroxide. The pH is probably too high to just add calcium to the water, because over 8.2 pH, calcium has difficulty dissolving at all.

The Switcheroo: Use the Orenda app to calculate the acid it will take to bring the pH down just below 7.8, based on your water tests. On the same calculator screen, figure out how much calcium you need to increase. When you tap "GET DOSAGE", you should see an amount of acid (fl.oz.) and an amount of calcium chloride (lb.). Grab a few clean buckets of water, and dissolve the necessary calcium, divided amongst the buckets evenly. Then divide the prescribed ounces of acid amongst the buckets too.  Stir until the solution turns clear and cools down. Then add the low-pH buckets of calcium rich water. This simultaneously lowers the pH of the pool, while replacing the LSI value that would be lost.

No, the switcheroo is not perfect, but it's effective at stopping the issue and allowing you to regain control of the chemistry. If and when we (or anyone else) figure out a better way to correct the chemistry, we will publish it immediately.

Missing the mark (high)

orenda startup fail, too much calcium on startup, calcium carbonate dust, not plaster dust, calcium snowingIf too much calcium is added to the water, or too quickly, it can have trouble staying in solution. Another way to overshoot the LSI is if you start adding calcium too late, like when the pool has been filling for a few hours already. This is one of the many reasons why it is critical to be there prior to the water turning on. We need to start from the beginning.

If we wait too long, there is already a pH spike going on in the pool, and it could already be over 8.2 pH in there. Sure, the tap water may be fine, but you're no longer dealing with just tap water. Adding calcium to the bowl with a pH that has already had time to rise will result in calcium not dissolving, and eventually falling out of solution as dust. This is not the same as plaster dust, but it is calcium carbonate. We call it "snow".

Snowing can happen when the SC-1000 and calcium are added too late (and the pH in the pool has already risen), OR by adding way too much calcium to begin with. Too much calcium is usually because of a flawed test of the tap water. The Orenda App's calculator is an accurate one, provided the inputs are accurate.

We had a recent example of a test that showed 120 ppm calcium in the source water...but in reality, the source water had 300 ppm calcium. Our procedure would have said to adjust alkalinity first...but instead, calcium was added, thinking there was only 120 ppm filling the pool. The result was a lot of snow that kept coming back, day after day.

Orenda Startup™ Failures look almost identical

Both overshooting and undershooting the LSI leads to dust, which uniformly falls onto the surface. High calcium hardness or high LSI does not have the ability to create unique marks and blemishes here and there, like straight lines, angles or foot prints. Calcium is blind, and if dust occurs, it's happening everywhere. Which brings us to our final point here:

An LSI Startup hides nothing

white calcium bowl bad exposure-1Any blemish or flaw left behind by the plaster application will likely be visible when doing the Orenda or Bicarb startup. Why? Because we are removing the water's ability to pull any calcium from the surface. If there are uneven areas of calcium carbonation (white marks), that excess calcium has nowhere to go. Traditional startups and hot starts pull calcium off the surface, and much of it carbonates into plaster dust to be brushed away. Not with ours.

If there are puddle marks, streaks, lines, footprints, rings, motting and other physical marks, you will probably see them. These imperfections will not be burned off, like they would during a hot start. We recognize this is can be seen as a burden and disadvantage for builders and applicators, because we all want the pool to look great. Everybody does...especially the customer.  When the exposure is done right, everybody is happy. When done wrong, nobody is happy.

Our startup is about preventing the loss of calcium so the cement in the plaster can cure properly. It neither creates nor conceals visible flaws from application or acid. 

water troweling copy

footprints on plaster

puddle hydration on plaster

Plaster Streaking

excess cream and blotches on plaster

clinker in plaster, pool clinker, cement clinker, clinker, pool plaster, calcium spot in pool

too many plaster issues to name

An Even Worse Exposure

Now again, a method like a hot start would burn off the outermost layer of the plaster surface, and many of these problems would be removed...but you would also be removing valuable calcium hydroxide from the surface, which compromises the surface long term. With an LSI startup like ours or the Bicarb startup, these marks stay.

Not only do we not cause these problems, our startup physically cannot cause these problems, nor remove them. We are open about the benefits AND limitations of our products and procedures. If you have marks like these, that's a separate issue that needs to be handled.

A refresher on how plaster dust forms

Aggressive water is hungry for calcium saturation, and will dissolve calcium until the LSI is balanced. The most soluble form of calcium in a new plaster surface is called calcium hydroxide, which has a very basic pH of 12.6. When water steals calcium hydroxide, the pH spikes (which is why the pH is always high during a traditional startup). That high pH also drives bicarbonate alkalinity to convert to carbonate alkalinity. Carbonate ions and dissolved carbon dioxide in the water bind to the calcium hydroxide coming out of the surface, and boom: you get calcium carbonate, which lands on the surface as plaster dust.


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